add check image function

AKAChing · web-flow · commit 8ebd4e2783de · 2020-03-09T11:40:16.000+08:00
diff --git a/CheckImage/index.js b/CheckImage/index.js
@@ -0,0 +1,47 @@
+/**
+ * @param {file} 文件对象
+ * @param {imgType} 图片格式限制 
+ * @param {size} 图片大小 
+ * @param {width} 图片分辨率宽度 
+ * @param {height} 图片分辨率高度 
+ * @param {equalRation} 是否开启等比限制
+ */
+export function checkImageFile(file, imgType = 'png', size = 1, width = 100, height = 100, equalRation = true ) {
+  const isCorrectImgType = file.type === `image/${imgType}`
+  const isLessThanSize = file.size / 1024 / 1024 < size
+  if (!isCorrectImgType) {
+    Message.error(`图片格式错误, 只能为${imgType}格式`)
+    return false
+  } else if (!isLessThanSize) {
+    console.log(isLessThanSize)
+    Message.error(`图片大小不能超过${size}MB`)
+    return false
+  } else {
+    return new Promise((resolve, reject) => {
+      const reader = new FileReader()
+      reader.onload = function(e) {
+        let image = new Image()
+        image.onload = function() {
+          let imgWidth = this.width
+          let imgHeight = this.height
+          if (equalRation) {
+            if (imgWidth !== imgHeight) {
+              Message.error(`图片比例必须为1:1`)
+              reject()
+              return false
+            }
+          } else {
+            if (imgWidth !== width && imgHeight !== height) {
+              Message.error(`图片分辨率必须为${width}像素x${height}像素`)
+              reject()
+              return false
+            }
+          }
+          resolve()
+        }
+        image.src = e.target.result
+      }
+      reader.readAsDataURL(file)
+    })
+  }
+}
